1 files changed, 69 insertions, 0 deletions
diff --git a/lib/java/src/main/java/org/apache/thrift/utils/StringUtils.java b/lib/java/src/main/java/org/apache/thrift/utils/StringUtils.java
new file mode 100644
index 000000000..b54388a5b
--- /dev/null
+++ b/lib/java/src/main/java/org/apache/thrift/utils/StringUtils.java
@@ -0,0 +1,69 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.thrift.utils;
+
+public final class StringUtils {
+
+  private StringUtils() {
+    // Utility class.
+  }
+
+  private static final char[] HEX_CHARS = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
+
+  /**
+   * Stringify a byte array to the hex representation for each byte.
+   *
+   * @param bytes the byte array to convert to hex string.
+   * @return hex string.
+   */
+  public static String bytesToHexString(byte[] bytes) {
+    if (bytes == null) {
+      return null;
+    }
+    return bytesToHexString(bytes, 0, bytes.length);
+  }
+
+  /**
+   * Stringify a portion of the byte array.
+   *
+   * @param bytes byte array.
+   * @param offset portion start.
+   * @param length portion length.
+   * @return hex string.
+   */
+  public static String bytesToHexString(byte[] bytes, int offset, int length) {
+    if (length < 0) {
+      throw new IllegalArgumentException("Negative length " + length);
+    }
+    if (offset < 0) {
+      throw new IndexOutOfBoundsException("Negative start offset " + offset);
+    }
+    if (length > bytes.length - offset) {
+      throw new IndexOutOfBoundsException("Invalid range, bytes.length: " + bytes.length + " offset: " + offset + " length: " + length);
+    }
+    char[] chars = new char[length * 2];
+    for (int i = 0; i < length; i++) {
+      int unsignedInt = bytes[i + offset] & 0xFF;
+      chars[2 * i] = HEX_CHARS[unsignedInt >>> 4];
+      chars[2 * i + 1] = HEX_CHARS[unsignedInt & 0x0F];
+    }
+    return new String(chars);
+  }
+}